A report by the Organisation for Economic Co-operation and Development (OECD) and UN-Habitat, the United Nations' lead agency for urban issues, found only 76 out of 150 countries have dedicated laws despite evidence that cities are key for sustainable economic growth.

What happens in urban areas is critical to national economic, social and environmental performance as cities generate more than 80 percent of global economic output, according to the World Bank.

They are also among the biggest polluters, struggling to balance growth with tackling environmental challenges as the proportion of people living in urban areas is forecast to grow to 66 percent by 2050 from just over half today.

About 90 percent of the countries surveyed are not taking climate change and environmental issues into consideration as part of national urban development priorities, the OECD said.

"We understand the need to prioritise growth," Lamia Kamal-Chaoui, who directs the OECD's cities programme, said at the report's launch at the World Urban Forum, the biggest conference on sustainable cities, in Kuala Lumpur on Friday.

"The traditional 'grow now, pay later' approach is not an option because it bears a lot of costs on society and the environment," she said. "It's very bad for business."

The OECD, which has been working with UN-Habitat, wants half of all countries globally to adopt explicit national urban policies by 2025.

The speed and scale of urbanisation brings challenges, including growing demand for affordable housing, efficient transport systems and basic services.

Mexico, one of the countries that has adopted a national urban policy, has already seen its benefits.

Since 2006 it has offered a housing subsidy to poor families, initially with no limit on where it could be used.

This often led to affordable housing popping up on the edge of big cities, where land was cheaper, Mexican housing commission director Jorge León Wolpert Kuri said.

But since adopting a national urban policy in 2014, the government has demarcated a boundary within urban areas outside of which the subsidy is not allowed.

"We did that to prevent cities from continuing to grow outward in a disorderly way," Wolpert Kuri told the Thomson Reuters Foundation.

"We wanted to create the conditions for people with lower incomes to live closer to the centre so they don't spend hours getting to work."

In Argentina, where 40 percent of the population live in the greater Buenos Aires area, the government is drafting a national policy hoping to create more even urban development elsewhere.

"We don't have a network of intermediate cities, which creates social fragmentation," said Marina Klemensiewicz, Argentina's secretary for habitat and human development, adding the dominance of Buenos Aires was a drag on productivity.

This article is culled from daily press coverage from around the world. It is posted on the Urban Gateway by way of keeping all users informed about matters of interest. The opinion expressed in this article is that of the author and in no way reflects the opinion of UN-Habitat.